This invention relates to a free standing fireplace hearth and a fuel composition for use therein.
In many patio, deck, back yard or other similar outside settings, an actively burning fire is often used to add significant ambiance to the setting. In addition to the visual appearance of the fire, the setting is enhanced by the soothing and pleasing crackling and popping sound of a wood burning fire. However, wood burning fires of this type often require significant attention to periodically add logs to maintain the fire. Wood burning fires generate a significant amount of ash, soot and the like thereby requiring clean up. Further, open kettles or the like which are commonly used to house the burning logs present a significant hazard and often do not adequately contain the fire during use thereby leading to the potential and dangerous spread of the fire through falling and burning logs, cinders or the like. Constant attention to the fire is thereby prudently required.
Therefore, there is a need for an improved outdoor fireplace or hearth which avoids these above-described drawbacks while still offering the visual and audible ambiance of a burning wood fire.
In a further aspect of the invention, it is highly desirable to provide a self-containing fire hearth which provides the ambience of a wood burning fire, that is a flame which has the appearance and sound of a wood burning flame, but without the necessity of wood fuel or cleanup of waste combustion products usually attendant a wood-fueled fire. Moreover and in this regard, it will be appreciated that an xe2x80x9cambiencexe2x80x9d fire or flame need not be measured by the typical parameters applied to a fire. For example, heat output, or BTUs, is a typical fire or heat performance criteria as is the heat producing efficiency from the fuel used. In a free-standing fire or hearth for ambience purposes, these parameters and efficiencies are relatively unimportant. In the case of heat production, the less heat produced, the better.
What is important are entirely different characteristics, namely burn time, fuel volume and burn characteristics. Thus, the efficiency of a decorative or ambient fire, for example, is measured in consideration of these parameters and their coalescence to provide the most desirable aesthetic result, with an acceptable burn time, at the least operational cost.
For example, acceptable burn characteristics require a fire with golden colored flame having random dancing patterns. A desirable burn time per fuel load is in the two to four hour range and the fuel cost per unit used should be low, compared to other systems within the above parameters.
Accordingly, it is a further objective of the invention to provide a freestanding fireplace hearth with an improved efficiency taking into account burn characteristics, volume of fuel used and burn time or duration per fuel unit consumed.
A further objective of the invention has thus been to provide a freestanding fireplace hearth with improved flame color and burning sound like a wood burning fire, at acceptable burn time and fuel volume used.
This invention overcomes the above-described and other drawbacks of known fireplace or hearth systems while still offering a visually and audibly pleasing safe live fire and associated ambiance in an outdoor setting.
In a presently preferred embodiment, the invention includes a free standing fireplace hearth for burning a fuel to provide an attractive ambiance fire in an outdoor setting. The fireplace hearth includes a base having a fuel tray defining a chamber slidably mounted therein on a drawer-like structure for movement between open and closed configurations and a spring biased latch to releasably secure the tray in the closed configuration. The tray is configured with a throat as an integral part of the overall combustion system as will be described. A snuffer or burner is disposed in the hearth over the tray and provides flaps or dampers for controlling the flame height and for snuffing out the flame as desired. The tray is mounted for movement on the drawer structure between a lowered and a raised position. A plurality of cams are pivotally oriented with respect to the tray. A stop is mounted on the base relative to the tray so that as the tray approaches the closed configuration, the tray abuts against the stop. Continued movement of drawer rails on which the tray is mounted toward the closed configuration activates the cams and thereby elevates the tray relative to the snuffer into the raised position and in operative contact with the snuffer.
A log set of fiber/ceramic or other wood simulation material is operably disposed over the snuffer. Flame from the snuffer dances up through passages in the log set which has features which glow. Air moving up the passages produces lift to enhance the burn characteristics of the flames.
A pair of spaced dampers or shutters are mounted for movement to and between a closed snuffing configuration and a fully open burn configuration. Each of the damper shutters are coupled via a linkage to a rotational control knob such that rotation of the control knob in a first direction pivots the damper shutters toward the closed snuffing configuration to extinguish the burning fuel. Rotation of the control knob in a second opposite direction pivots the damper shutters toward the fully open configuration to increase the flame height through the log set.
A plurality of posts extend upwardly from the base to support a roof. The roof includes a heat shield mounted on the interior thereof to deflect hot air generated by the burning fuel from impinging upon the roof and thereby maintains the roof at a lower temperature than the heat shield during fuel burning. At least a portion of the heat shield is spaced from the roof to define space for an insulation layer of air between the heat shield and the cover. A plurality of baffles are included on the heat shield to direct the heat out from under the roof, off of the heat shield and cooler air into the insulation layer of air between the roof and the heat shield.
The present invention in another aspect includes a specific composition of fuel which is suitable for use in the free standing fireplace hearth. The fuel in a presently preferred embodiment is a gel composition which satisfies the characteristics of fireplace fuel with respect to aesthetic features such as producing golden high luminous flame without producing an offensive odor or smoke while still generating a crackle and pop sound. Further, the fuel is safe for handling and storage purposes and the formulation is of generally non-toxic components as well as being self-contained if spilled, environmentally safe in burning, producing minimal pollutants and being readily extinguishable without any smoke buildup. Further, the burnt fuel does not produce any significant amount of residue or the like.
Accordingly, it will be appreciated that the fuel tray, the fuel chamber throat in the tray, the snuffer with its dampers and the log set combine to define a combustion system producing a flame having the random pattern appearance of a wood flame with desirable burn time and low fuel volume requirements.
In brief, the combustion system performs or acts something like a carbueration system.
When the drawer is shut the fuel chamber mates or couples with the snuffer assembly to complete the combustion system and also acts as a way to extinguish the flame. Air is mixed with the fuel. The fuel vaporizes in the fuel chamber and the air-alcohol gas mixture rises or moves through the throat out of the chamber via a plurality of flame paths created by a wedge-shaped, diverter of the snuffer and the openings on top of the snuffer assembly. The damper or doors control the height of the flames and also act when closed to snuff out the flame. The log set is decorative. As the flames move through the log set, they actually warm the log set material causing it to glow when touched by flame. The flames move through the log set with as little impingement as possible so that sooting is kept to a minimum. The passages in the log set warm up and cause convection of additional ambient air up through the passages so the fire or flame is decoupled and is lifted up therethrough. The system is self-regulating, so as the user adjusts the dampers, increasing or decreasing the size of the flame, the combustion system continues to work the same way.
A preferred fuel according to the invention is a gel composition, or mix of a lower alkyl alcohol, water, flammable organic tertiary butyl alcohol and double or single walled microencapsulated solvents, gelling agent, polyacrylic acid, cross linking agent and surfactant. Such a fuel as described herein, when used in the hearth described herein, produces desirable burn characteristics over an acceptable burn time and with an acceptable fuel volume required.